rose.config_processors.jinja2: $NAME in values.

Allow $NAME and ${NAME} in values in "jinja:suite.rc" sections.
Tweaked a ambiguous line.
Update CHANGES.md
rose.resource: fix split problem.

Python bad split behaviour was causing a path search of $PWD.
Merge pull request #692 from matthewrmshin/jinja2.suite.rc.value.env_process

rose.config_processors.jinja2: $NAME in values.
Merge pull request #693 from arjclark/rose-training-doc-update

documentation tweak following training
Merge pull request #694 from matthewrmshin/fix.split

rose.resource: fix split problem.
Merge branch 'master' of github.com:metomi/rose into metomi-gh-pages